Kindness is one of those happiness paradoxes, whereby we become happier by making other people happier.

“We often are pursuing our own interests most effectively by laying them aside and serving others,” says Stefan Klein in Survival of the Nicest.

This week focuses on the benefits of being kind, but these aren’t the only benefits of a kind act. Two other groups of people can benefit, too: the recipient, of course, and the observers. That warm, fuzzy feeling or chills we get when we see a kind act is called elevation, and it’s one of the reasons kindness is so contagious.

But for now, read on to see what benefits you can expect as you cultivate kindness:

More happiness and positive emotions

As we learned in week 1, our brains love kindness – our neurological reward systems show similar activity when we win money and when the same money goes to a charity of our choice. When our romantic partners are receiving electric shocks and we comfort them by holding their arm, the brain’s reward circuitry also activates. In short, when we give, our brains looks like they are gaining something – and the pleasure we feel makes us more likely to give in the future.

Research by Elizabeth Dunn at the University of British Columbia found that people given $50 who spend it on others are happier at the end of the day than people who spend it on themselves. The same goes for a work bonus of a few thousand dollars – even though, beforehand, people say they’d much prefer to spend the money on themselves. We are even happier when we remember buying things for others than when we remember buying things for ourselves. And the more generous we are in general – the more money we spend on gifts and donations – the happier we tend to be.

So giving is pleasurable, but what about helping? It might seem easier to spend money on others than to spend time on them, but it turns out both forms of kindness make us happier. A study of more than 3,000 people found that 95% of people feel good when they help someone, 53% of people feel happier and more optimistic, and those feelings last hours or even days for 81% of people. The “helpers’ high” is a real phenomenon.

A 2001 study found that regular volunteering increases happiness, life satisfaction, self-esteem, and sense of control over life. And it works for young and old alike: black inner-city teens who tutor younger children have more positive attitudes toward the self, others, their education, and the future; and elderly people who volunteer are more satisfied with life.

In this TEDx talk, Botlhale Tshetlo explains how gratitude led her to perform 38 random acts of kindness for her 38th birthday, and the impact it had on her:

Better relationships

When we’re kind, we show someone that they mean something to us. Even if they are a stranger, we’re saying: your life matters. That kind of attention is special: it will usually induce gratitude, and we know all the benefits that gratitude has on relationships.In a hectic world, even a kind word or a small gesture can snap us out of a bad mood, brighten our day, and bring us closer to the giver. The kindness of strangers can be even more moving, since it’s so unexpected.

A study of over 10,000 people ages 20-25 from 33 countries found that kindness was more attractive than good looks. It seems people are listening to the typical dating advice: you can tell how a man will treat you by the way he treats the waiter.

One reason kindness is good for relationships is that kind people are more empathic. Duke University professor Scott Huettel found that more selfless people have more activity in the posterior superior temporal cortex, the part of the brain associated with taking someone else’s perspective and understanding their actions. Those skills are key in relationships, where feeling seen and understood is part of the glue holding people together.

Watch journalist Christiaan Triebert tell his story of hitchhiking from the Netherlands to South Africa – and what he learned about the connective power of kindness:

Better health

Kindness can also be a route to better health and longer life.

Kindness strengthens our immune system, reduces aches and pains, improves our cardiovascular profile, and boosts energy and strength in elderly people. In a 2006 study, the most loving and kind couples were shown to have the lowest levels of atherosclerosis (clogging of the arteries).

Various studies in the past 15 years have shown that regular volunteers have better health and (among the elderly and those with HIV/AIDS) a lower mortality rate.

So how often should we be out volunteering? A study by Allan Luks, famous for researching the “helpers’ high,” found that weekly volunteering makes you 10x more likely to experience health benefits than annual volunteering. Among older people ages 64-68, an Australian National University study found that we get the greatest health benefits from volunteering about 2-4 hours a week and little benefit from any time beyond that.

Even witnessing kindness might be good for us: a 1988 Harvard study found that participants who watched a 50-minute video about Mother Teresa had elevated levels of salivary immunoglobulin-A, which protects us from pathogens in food.

Author David Hamilton explains the biology of kindness and its health benefits in this talk:

Fewer negative emotions and better coping

Over the past 15 years, various studies have shown a connection between kindness, altruism, and volunteering and less depression. For volunteers, this is the case as long as they don’t go overboard and overburden themselves by giving too much or too often. Being unkind to ourselves – via low self-compassion – is also connected to depression and low psychological well-being.

Oddly enough, those of us who are struggling might be some of the best candidates for kindness. Over the years, studies of people fighting disease, chronic pain, and emotional trauma have shown that kindness can help them cope better and combat negative emotions.

A 2004 Brown University study, for example, found that alcoholics who help other alcoholics have a 40% sober rate the next year, compared to 22% among alcoholics who didn’t help others. For patients with chronic back pain, helping other chronic pain sufferers actually decreased the intensity of their pain. And HIV patients who practice altruism can lower their stress levels.

In this talk, teacher Ferial Pearson explains how organizing a group of “secret kindness agents” helped her overcome her fears after the Sandy Hook school shooting and helped her students deal with difficult life circumstances:

Self-kindness is equally important for coping. When we’re ill or troubled, it’s easy to blame ourselves and think of all the things we could have done better, everything that’s wrong with us, all the opportunities we missed. Self-kindness is a way to find some peace and acceptance, and to care for ourselves the way we would care for a loved one in our situation. Chronic acne sufferers who practiced self-compassion for two weeks – including challenging their inner critic and writing a self-compassionate letter – experienced less shame and depression as well as less physical burning and stinging due to acne.

When self-critical people fail, their brains go into problem-solving mode; they feel more negative and try to avoid the reality of failure. When self-compassionate people fail, brain areas related to positive emotions and compassion activate, and they tend to be more positive and accepting. If you force self-compassionate people to list the worst things that have ever happened to them, they tend to comfort themselves and feel that everyone has been through a similar experience, while self-critical people feel negative and worse off than others.

In short, trauma presents an opportunity: do we beat ourselves down even further, or give ourselves the care and comforting that we so desperately need? So many of us choose the former, but the benefits of self-kindness can be revolutionary.

Better performance

Finally, there’s some evidence that kind people – far from being pushovers – actually perform better. A 1973 study found that black inner-city teens who tutor 4th and 5th graders improve in their math, reading, and sentence completion skills. Another study, this time in the 90s by the US National Volunteer Service Program, found that high school students who are assigned to volunteer work had fewer teen pregnancies, fewer suspensions, and better grades at school.

In the wake of the 2004 tsunami, companies that donated to relief efforts saw an unexpected increase in their stock price, with bigger increases for higher donations. The only charitable corporations whose stocks didn’t go up donated exactly $1 million, which the public might have seen as a PR stunt.

KIND Healthy Snacks is a company based on a foundation of kindness – to self (with healthy food) and to others. Each month, they donate $10,000 to a cause and help people engage in random acts of kindness, like this one:

Why kindness is good

Each act of kindness might seem small, but it’s actually changing the way we see ourselves, the way we see others, and the way others see us.

As our kind actions affect the lives of others, we feel more compassionate, confident, useful, and in control. At the same time, we may also feel less guilty or distressed at the problems in our neighborhood and our world because we’re doing our part to make a difference. In our normal lives, we may find ourselves feeling more grateful for what we have, and optimistic about the future.

As we interact with the people we’re helping, we may start seeing others more positively rather than justifying our lack of help by putting them down – if they’re homeless, they must not be trying to get a job. We may start to give people the benefit of the doubt, and even see a larger web where we’re all connected and interdependent.

In turn, we become a different person – and others notice that. We become more likable, more trusted, and more worthy of help ourselves, completing the circle of kindness.